The heavy-fermion superconductor CeRh2As2 features two distinct superconducting phases with a high-field phase emerging for (out-of-plane) magnetic fields exceeding 4T. I will discuss the peculiar crystal symmetry of CeRh2As2 and show how its phase diagram can be understood from the perspective of local-inversion-symmetry breaking: the situation, where inversion is broken locally in a sublattice, but retained globally. After an analysis of the magnetic response in a model system consisting of layers with alternating Rashba spin-orbit coupling to identify possible superconducting orders, I will present a Ginzburg-Landau picture of the full phase diagram.
The good qualitative agreement of this theoretical phase diagram with the experimental phase diagram suggests that the physics of local non-centrosymmetry plays a crucial role in this compound.
